diff --git a/tools/exp/rdf/rfc/ontology.go b/tools/exp/rdf/rfc/ontology.go
index e4aed1c..0c0857b 100644
--- a/tools/exp/rdf/rfc/ontology.go
+++ b/tools/exp/rdf/rfc/ontology.go
@@ -14,6 +14,7 @@ import (
 const (
 	rfcSpec   = "https://tools.ietf.org/html/"
 	bcp47Spec = "bcp47"
+	mimeSpec  = "rfc2045" // See also: rfc2046 and rfc6838
 )
 
 type RFCOntology struct {
@@ -36,6 +37,12 @@ func (o *RFCOntology) LoadAsAlias(s string) ([]rdf.RDFNode, error) {
 			Name:     bcp47Spec,
 			Delegate: &bcp47{pkg: o.Package},
 		},
+		&rdf.AliasedDelegate{
+			Spec:     rfcSpec,
+			Alias:    s,
+			Name:     mimeSpec,
+			Delegate: &mime{pkg: o.Package},
+		},
 	}, nil
 }
 
@@ -50,6 +57,15 @@ func (o *RFCOntology) LoadSpecificAsAlias(alias, name string) ([]rdf.RDFNode, er
 				Delegate: &bcp47{pkg: o.Package},
 			},
 		}, nil
+	case mimeSpec:
+		return []rdf.RDFNode{
+			&rdf.AliasedDelegate{
+				Spec:     "",
+				Alias:    "",
+				Name:     alias,
+				Delegate: &mime{pkg: o.Package},
+			},
+		}, nil
 	}
 	return nil, fmt.Errorf("rfc ontology cannot find %q to alias to %q", name, alias)
 }
@@ -63,6 +79,8 @@ func (o *RFCOntology) GetByName(name string) (rdf.RDFNode, error) {
 	switch name {
 	case bcp47Spec:
 		return &bcp47{pkg: o.Package}, nil
+	case mimeSpec:
+		return &mime{pkg: o.Package}, nil
 	}
 	return nil, fmt.Errorf("rfc ontology could not find node for name %s", name)
 }
@@ -146,3 +164,83 @@ func (b *bcp47) Apply(key string, value interface{}, ctx *rdf.ParsingContext) (b
 	}
 	return true, nil
 }
+
+var _ rdf.RDFNode = &mime{}
+
+type mime struct {
+	pkg string
+}
+
+func (*mime) Enter(key string, ctx *rdf.ParsingContext) (bool, error) {
+	return true, fmt.Errorf("MIME media type cannot be entered")
+}
+
+func (*mime) Exit(key string, ctx *rdf.ParsingContext) (bool, error) {
+	return true, fmt.Errorf("MIME media type cannot be exited")
+}
+
+func (m *mime) Apply(key string, value interface{}, ctx *rdf.ParsingContext) (bool, error) {
+	v := ctx.Result.GetReference(rfcSpec)
+	if len(v.Values[mimeSpec].Name) == 0 {
+		u, err := url.Parse(rfcSpec + mimeSpec)
+		if err != nil {
+			return true, err
+		}
+		val := &rdf.VocabularyValue{
+			Name:           mimeSpec,
+			URI:            u,
+			DefinitionType: jen.String(),
+			Zero:           "\"\"",
+			IsNilable:      false,
+			SerializeFn: rdf.SerializeValueFunction(
+				m.pkg,
+				mimeSpec,
+				jen.String(),
+				[]jen.Code{
+					jen.Return(
+						jen.Id(codegen.This()),
+						jen.Nil(),
+					),
+				}),
+			DeserializeFn: rdf.DeserializeValueFunction(
+				m.pkg,
+				mimeSpec,
+				jen.String(),
+				[]jen.Code{
+					jen.If(
+						jen.List(
+							jen.Id("s"),
+							jen.Id("ok"),
+						).Op(":=").Id(codegen.This()).Assert(jen.String()),
+						jen.Id("ok"),
+					).Block(
+						jen.Return(
+							jen.Id("s"),
+							jen.Nil(),
+						),
+					).Else().Block(
+						jen.Return(
+							jen.Lit(""),
+							jen.Qual("fmt", "Errorf").Call(
+								jen.Lit("%v cannot be interpreted as a string for MIME media type"),
+								jen.Id(codegen.This()),
+							),
+						),
+					),
+				}),
+			LessFn: rdf.LessFunction(
+				m.pkg,
+				mimeSpec,
+				jen.String(),
+				[]jen.Code{
+					jen.Return(
+						jen.Id("lhs").Op("<").Id("rhs"),
+					),
+				}),
+		}
+		if err = v.SetValue(mimeSpec, val); err != nil {
+			return true, err
+		}
+	}
+	return true, nil
+}
diff --git a/tools/exp/spec.json b/tools/exp/spec.json
index ea6439d..faa1204 100644
--- a/tools/exp/spec.json
+++ b/tools/exp/spec.json
@@ -4192,7 +4192,7 @@
           "isDefinedBy": "https://www.w3.org/TR/activitystreams-vocabulary/#dfn-mediatype",
           "range": {
             "type": "owl:Class",
-            "unionOf": []
+            "unionOf": "rfc:rfc2045"
           },
           "name": "mediaType",
           "url": "https://www.w3.org/TR/activitystreams-vocabulary/#dfn-mediatype"